Modern transportation requires the extensive use of over-the-road vehicles such as automobiles, vans, trucks, and the like. Presently, such vehicles are powered by an engine which is fueled by gasoline or diesel fuel. The use of such fuels has given rise to two apparent shortcomings. First, such fuels are in limited supply throughout the world and the international control of such fuels causes their price and availability to be uncertain. A second shortcoming of such fuels is their adverse impact on the environment. It is generally believed that the hydrocarbon gases released from the combustion of gasoline or diesel fuel in an internal combustion engine is environmentally undesirable.
It is know that natural gas is in bountiful supply in the United States and that the burning of such gas is environmentally compatible. It is also known that internal combustion engines can operate efficiently on natural gas. However, the use of natural gas as a vehicle fuel has been constrained by the "range" afforded the vehicle using such fuel. In the past, tanks of compressed natural gas have been placed in the trunk or other storage areas of the vehicle and interconnected with the fuel system for passage to fuel injectors or the like. However, the availability of storage areas in vehicles suitable for receiving such tanks of compressed natural gas is somewhat limited and such limitation necessarily constrains the distance that the vehicle can travel without refueling. Accordingly, the range of vehicles employing natural gas fuel has necessarily been significantly limited in the past.
The prior art has been substantially devoid of the presentation of a vehicle having an internal combustion engine and having fuel tanks provided as an integral portion of the vehicle to serve for holding natural gas fuel for use by the engine. The requirement that the natural gas be introduced into the fuel tanks at high levels of pressure have typically dictated that the tanks be specially designed for simple retention in storage areas of the vehicle, and the prior art has not envisioned a manner for incorporating fuel tanks as a structural portion of the vehicle itself. Indeed, the prior art has not taught fuel tanks of sufficient strength to receive and maintain large volumes of natural gas at high pressure levels, while serving as a structural element of the vehicle. Indeed, the prior art has envisioned the use of natural gas as the fuel for vehicles as being more of a novelty feature for use by vehicle fleets serving a limited area, rather than as a practical means for avoiding the shortcomings inherent in the use of gasoline and diesel fuels.